Drill bit



July 24, 1956 H. BESSLER DRILL BIT 2 Sheets-Sheet 1 Filed April 2, 1954 INVENTOR.

HENRY H. BESSLER July 24, 1956 H. H. BESSLER 2,756,023

DRILL BIT Filed April 2, 1954 2 Sheets-Sheet 2 2 INVENTOR.

HENRY H. BESSLER AGENT DRILL BIT Henry H. Bessler, Angora, Minn. Application April 2, 1954, Serial No. 420,588 3 Claims. 01. 255-61) This invention relates to a drill and has special reference to a rotary bit for earth drilling such as in mining operations and the like.

There has long been a search for an adequate drill bit for drilling hard material such as iron ore, and the like, wherein the drilling may be accomplished at a rapid pace without consuming too much power or requiring excessive changing of drill bits and the like due to the latter becoming dull quickly through use.

There has also been a long search made for a drill bit which is capable of drilling a relatively large diameter hole quickly and efliciently.

It is one of the principal objects of the present invention to provide a drill bit which satisfies the above mentioned needs.

Another object of the present invention is to provide a drill bit which is of strong construction for greater durability and wherein the cutting members of the drill are made from a difierent metal than the drill body and are carried by the drill body in such a manner that they are rigid and may be sharpened when the need arises for such.

Another object of my invention is to provide an efficient means for mounting the drill bit on the drill shank.

A more specific object of my invention is to provide a drill body of cast steel having suitable grooves therein to receive the special tungsten carbide cutting blades, the drill body being of one piece and also having means to receive the drill shank integral therewith.

Another object is to provide a drill bit wherein the cutting edges of each of the blades are disposed in two different planes and wherein the bit will drill its own pilot hole.

These and other objects and advantages of my invention will become more apparent as the description proceeds.

In the accompanying drawing forming a part of this application:

Fig. 1 is a perspective view of the head of the drill bit showing the cutting blades in place.

Fig. 2 is an end view of Fig. 1.

Fig. 3 is a View similar to Fig. 2 of another form of my invention with the blades removed and illustrating grooves to receive the cutting blades.

Fig. 4 is a side elevational view, partly in section, of the complete drill bit.

Fig. 5 is a top plan view of the invention shown in Fig. 4.

Fig. 6 is a side elevational view of one of the blades.

Fig. 7 is an end view of Fig. 6.

In the drawing the reference numeral 1 indicates the head of my drill bit and 2 indicates the shank thereof. The shank 2 includes a tapered end member 3 to be received within the similarly tapered opening 4 within the drill rod 5. A threaded portion 6 is provided at the lower end of the tapered portion 3 to be received in the similarly threaded portion 7 of the rod 5. A shoulder 8 is provided at the end of the threaded portion 6, the

United States Patent O 2,756,023 Patented July 24-, 1956 end 9 of the rod 5 preferably being designed to abut the shoulder 8 as shown. Between the shoulder 8 and the head 1, the shank 2 is preferably provided with flattened surfaces 10, as shown, to permit a wrench to be employed to tighten the threaded portion 6 into the threaded portion,7 as shown.

The tapered portion 3 of the shank 2 preferably fits snugly into the tapered opening 4, as shown, so that a solid connectionis provided between the drill rod 5 and the shank 2 whereby maximum strength of the connection is obtained and maintained during the operation of the drill bit.

The head 1 of my bit is of generally frusto-conical shape as shown and is provided with a plurality of hollowed-out areas 1111 extended from the top thereof to the bottom thereof. The hollowed-out areas 11 serve to permit the material which is cut loose in drilling to pass upwardly out of the way of the cutting blades 12. The head 1 is provided with a plurality of grooves 13--13 in which the blades 12 are fixedly mounted as by soldering, Welding, or the like. The grooves 13 extend from the bottom of the head 1 to the upper end thereof. There are preferably four grooves in the head 1, as shown, each of which receives a blade 12, and the head may have a flat seat portion 18 at its smaller end which may or may not be provided with a plurality of grooves 26 therein (see Fig. 3), the purpose of which will become apparent as the description proceeds.

The blades 12 are preferably of tungsten carbide steel and are provided with a leading edge 14 and a trailing edge 15, which run the length of the head 1. The lower end or point of the drill bit is composed of inward extensions 16 on each of the blades, the extensions having a flat upper surface 17 which is seated on the flat seat portion 18 at the lower end of the head 1 whereby the blades are firmly seated on the head to withstand the thrust encountered in the drilling operation.

As shown in the accompanying drawings, the blades 12 are mounted in opposed pairs, with the leading edges of the opposed blades being in alinement with each other, see Fig. 2. The extensions 16 of the blades abut each other at the central apex 19 of the cutting extensions, and have a leading or cutting edge 20 which extends inwardly from the cutting edge 14. The cutting edges 20 meet at the center apex 19 of the cutting extensions and form a continuation of the cutting edges 14-. The cutting edges 20 of the extensions 16 extend in angular relation to the cutting edges 14 of the blades as shown, and meet at the central apex 19, forming the leading portion 22 of the drill bit immediately adjacent the apex point 19 which serves to cut its own pilot hole, the portion 22 being rather blunt or having a flat taper as compared with the major portion of the drill body 1.

To rigidify the point 22 of the drill to accommodate the vertical as well as the rotary thrust, I prefer to weld the abutting inner edges 23 of the blades to their adjacent blades as at 24, thus making the point a very rigid and strong structure.

If desired the upper edges 17 of the extensions 16 may be welded as at 25 to the flat seat portion of the head 1, or if desired suitable openings or grooves 2d may be provided in the fiat seat portion 18 of the head 1. The grooves 26 are arranged across the seat portion 18 as continuations of their respective grooves 13, and they extend toward the longitudinal axis of the head Where they meet at the center of the seat 18 as shown, to receive the edges 17 of the extensions 16 of the blades to rigidify the connection of the blades to the drill head.

In order to provide a sharp cutting point for my drill bit I have chamfered the trailing edges 27 of the extensions 16 as at 28 at'the inner edges thereof whereby the cutting edges 20 come to a sharp point.

The leading edges of the blades 12 project beyond the trailing edges thereof on the major portion of the blades on the extension 16, see Figures 2 and 5. This arrangement permits the cutting action, of course.

It will be deemed apparent that the blades of my drill bit, as here shown, may be readily sharpened a considerable number of times inasmuch as the blades extend outwardly from the head 1 at a substantial distance as at 29, thus permitting repeated use of my drill bit.

The drill bit above described will cut, rapidly through relatively hard material such as iron ore and the like, to make relatively large holes, it being preferred that my drill bit have a cutting diameter of at least twelve inches. The drill provides plenty of space for removing the waste materials as may be readily seenfrom the open areas 11 when compared with the diameter of the opening drilled suggested by the dotted lines at 30.

It is preferred that the upper end of the drill shank 2 be provided with a threaded opening 50 axially thereof to permit the handling of the bit. A suitable eye bolt, not shown, may be threadedly mounted in the opening 50 to permit the drill bit to be handled by a winch or the like when desired.

Having thus described my inventionwhat I claim is:

1. A drill bit comprising: a head member, a shank extending from one end of said head member, said head being of generally frusto-conical shape and having a plurality of longitudinal blade receiving grooves in the outer surface thereof, the smaller end of said head being the lower end thereof and terminating in a flat seat, a blade fixed in each of said grooves and extending outwardly therefrom, each of said blades having an extension at their, lower end which extends beyond the end of said head and inwardly to the longitudinal axis of said bit, said extension having an upper surface seated on said seat, and a lower surface downwardly inclined with respect to said seat, said extensions abutting each other and being fixed together and to said head adjacent the axial center of said bit, said blades each having a straight cutting edge on their outwardly extending portions, each of said extensions having a cutting edge on said inclined surface, said head being provided with longitudinal grooves between said blades to allow the passage of waste materials from said cutting blades, said cutting edges of said extensions extending in the same radial plane as said cutting edges of said blades, and said lower surface of said extensions opposite the cutting edges thereof being beveled toward the axial center of said bit to provide a sharp leading point for said bit.

2. A drill bit in accordance with claim 1 in which each of the blades is made of a harder metal than the head.

3. The structure as set forth in claim 1 and said extensions being welded together where they abut to provide rigidity for said leading point.

References Cited in the file of this patent UNITED STATES PATENTS 1,510,871 Swaim Oct. 7, 1924 1,577,810 Raymond Mar. 23, 1926 2,337,720 Koeln Dec. 28, 1943 

